Hydrogen peroxide from alkylhydroperoxides

ABSTRACT

When aliphatic and alicyclic hydroperoxides are converted to their corresponding peroxides with about a 50 percent concentration of acid, hydrogen peroxide can also be recovered in good yield from the reaction mixture by carrying out the process in the presence of a stannate salt or an orthophosphoric acid stannous halide reaction product.

United States Patent Turner Apr. 4, 1972 [54] HYDROGEN PEROXIDE FROM2,497,814 2/ 1950 Elston ..23/207.5 ALKYLHYDROPEROXIDES 2,522,016 9/1950Denison, Jr. et al ..260/61O B [72] Inventor: John 0. Turner, WestChester, Pa. Primary Examiner oscar R vemz [73] Assignee: Sun OilCompany, Philadelphia, Pa. Assistant Examiner-Hoke MillerAttorney-George L. Church, Donald R. Johnson, Wilmer E. [22] Flled: 1970McCorquodale, Jr. and Stanford M. Back 2] A 1. No.1 2 681 1 pp 57ABSTRACT [52] U.S. Cl. ..23/207.S, 260/610 R h n aliphatic and alicyclichydroperoxides are converted to [51] lnt.Cl. ..C01b 15/02, C07c 13/00their C r sponding peroxides with about a 50 percent con- [58] Field ofSearch ..23/207, 207.5; 260/502 R, 610 A, centration of acid, hydrogenperoxide can also be recovered in 260/610 B, 610 D, 610 R; 252/397 goodyield from the reaction mixture by carrying out the process in thepresence of a stannate salt or an orthophosphor- [56] References Citedic acid stannous halide reaction product.

UNITED STATES PATENTS 5 Claims, No Drawings HYDROGEN PEROXIDE FROMALKYLHYDROPEROXIDES BACKGROUND OF THE INVENTION This invention relatesto a novel method of preparing hydrogen peroxide. More particularly, itrelates to a method of forming hydrogen peroxide during the conversionof an aliphatic or alicyclic hydroperoxide with a 30 to 65 percentconcentration of acid to the corresponding peroxide.

In U.S. Pat. No. 2,522,016 there is taught the preparation of organoperoxides by contacting an organo hydroperoxide with a strong acid. Itis specifically stated in this patent that the reaction does not evolvehydrogen peroxide or oxygen.

U.S. Pat. No. 1,958,204 teaches that solutions of hydrogen peroxide arestable in the presence of sulfuric or phosphoric acid if the pH ismaintained at about 1 to 3. This patent further teaches that stabilityofthe hydrogen peroxide solution is improved if sodium stannate is added,provided that the pH of the solution is maintained at greater than 3.5,and preferably in the range of from about 4 to 5, since the tin compoundis precipitated from solution at pHs below 3.5, unless other salts areadded, in which case the pH may be as low as 2.0.

Finally, W. C. Schumb, in Industrial and Engineering Chemistry, Vol. 41,No. 5, pages 992-1003 (1949) again indicates that hydrogen peroxide ismost stable at pH 4, and that it decomposes at high rate at pH's aboveand below this point. This article also shows that at these pH rangesthe addition of certain compounds such as stannate or pyrophosphatesalts will prolong the stability over long periods of time bystabilizing these solutions against the effects of metal ions such asiron, copper, and the like which catalyze the decomposition of thehydrogen peroxide.

It is thus evident that none of these foregoing references, or any ofthe prior art cited in these references, constitutes a teaching of thepossibility of recovering hydrogen peroxide during the conversion of anorgano hydroperoxide to its corresponding peroxide in an acid medium,and certainly not at pHs substantially below 1.0. Indeed, US. Pat. No.2,522,016 clearly teaches the opposite, i.e., that hydrogen peroxide isnot produced when an hydroperoxide is treated with an acid.

SUMMARY OF THE INVENTION Notwithstanding these prior art teachings, ithas now been found that hydrogen peroxide can be obtained in good yieldtogether with an alkyl peroxide by reacting an aliphatic or alicyclichydroperoxide with 30 to 65 percent concentrations of acid in thepresence of stannate salt or an orthophosphoric acidstanous halidereaction product. The pH of the reaction medium at these acidconcentrations is below about 0.5

DESCRIPTION OF THE INVENTION The process of this invention isconveniently carried out by adding the desired hydroperoxide to anaqueous acidic medium to which has also been added a selective additive,allowing the reaction to proceed for from 5 to hours at temperatures offrom 40 to 65 C., and then recovering and separating the resultingmixture of aliphatic or alicyclic peroxide and hydrogen peroxide.

The additives which have been found to ensure the formation andstabilization of the hydrogen peroxide in this type of reaction mediumcomprise alkali .metal salts of tin'such as sodium stannate, or thereaction product of orthophosphoric acid and stannous halide (as taughtin U.S. Pat. No. 2,091,178) in amounts which provide from 0.01 to 3.0grams of additive for each 9 to 10 grams of hydroperoxide startingmaterial, and preferably about 0.1 to 1.5 grams of additive.

It is desirable, although not essential, that the reaction be free ofthose metal ions which are particularly known to catalyze thedecomposition of hydrogen peroxide, namely iron, copper or chromiumions. Thus, it is preferred that the starting materials avoid saltscontaining these metals wherever possible.

The acids employed in this process include the inorganic acids such ashydrochloric, phosphoric, polyphosphoric, sulfuric, and perchloric, aswell as various sulfonic acids or acidtreated molecular sieves. Ofthese, sulfuric acid is preferred. It is important that the acidconcentration be between about 30 to 65, and preferably 45 to 55 weightpercent based on the total weight of aqueous acid solution, to ensurebest results. At these concentrations, the pH of the reaction medium isbelow about 0.5.

The hydroperoxide starting materials include both aliphatic andalicyclic compounds having from about three to 12 carbon atoms. Thesehydroperoxides may be either secondary or tertiary compounds, althoughthe latter type are more reactive and are thus preferred. Includedamongst the hydroperoxides useful in carrying out this process are suchcompounds as tbutyl hydroperoxide or sec.-butylhydroperoxide, l-methylcyclopentylhydroperoxide, 1-methylcyclohexylhydroperoxide, and the like.When these compounds are treated in accordance with this process, thereare obtained the corresponding di-aliphatic or di-alicyclic peroxidestogether with hydrogen peroxide in good yield.

The organic peroxide and hydrogen peroxide may readily be recovered fromthe reaction medium by phase separation, i.e., separation of the organicphase containing the peroxide from the aqueous acid phase containing thehydrogen peroxide. Advantageously, the hydrogen peroxide may be left inits acidic medium and used directly in that form in such reactions asthe Baeyer-Villiger oxidation, in the epoxidation of olefins and thelike.

This invention also relates to a process for stabilization of hydrogenperoxide in an aqueous acidic medium containing an aliphatic oralicyclic peroxide which comprises adding an alkali metal stannate orthe reaction product of orthaphosphoric acid and a stannous halide tosaid aqueous acidic medium wherein the amount of acid and stannatestabilizer are the same as that indicated in Examples 5 to 7 below, aswell as throughout the preceding description.

The following examples illustrate the invention. In each of theseexamples the reaction media were substantially free of iron, copper, andlike metal ions which are known to catalyze the decomposition ofhydrogen peroxide.

EXAMPLE 1 The following example illustrates the relative stability ofhydrogen peroxide alone in the acid concentrations employed in thisprocess:

A solution containing 177 g. of 61 percent H SO, and 33 g. of 30 percenthydrogen peroxide, was stirred for 2 days at 50 C. The initialconcentration was 4.7 percent weight hydrogen peroxide in 51 percent HAliquots were removed periodically and titrated for hydrogen peroxide.It was found that less than 2 percent of the hydrogen peroxide haddecomposed during the 2-day period.

EXAMPLE 2 The following example illustrates the substantial absence ofhydrogen peroxide as a reaction product in the conversion of anhydroperoxide to a peroxide by treatment with acid:

Nine grams (0.1 moles) of t-butylhydroperoxide were added to 25 cc. of50 weight percent aqueous H 80, and stirred at 50 C. for 15 hours. Phaseseparation yielded 6.75 g. (0.46 moles) of di-t-butylperoxide (92percent of theory) and a water. white acid phase that contained onlytraces of hydrogen peroxide 1 percent of theory).

EXAMPLE 3 The following example illustrates the marked instability ofhydrogen peroxide in the presence of the hydroperoxide and acid startingmaterials:

A solution containing 9 g. (0.1 mole) t-butylhydroperoxide, 3.1 g.hydrogen peroxide, 37 g. 96 percent sulfuric acid and 31 g. water werestirred at 50 C. for 15 hours. The overall acidity was approximately 50weight percent and the conditions were similar to those of Example 2except that hydrogen peroxide was added to see if it would survive thereaction. Analysis showed only traces of hydrogen peroxide 1 percent oftheory) and a 50 percent yield of t-Bu O EXAMPLE 4 EXAMPLE 5 A solutioncontaining 9.0 g. (0.1 mole) of t-BuOOl-l in 33 g. of 50 percent weightaqueous H 80 with 1.0 g. of sodium stannate (Na,SnO;,-b3l-l,0) wasstirred at 50 C. for hours.

Analysis of the acid layer showed that 1.1 g. of hydrogen peroxide (63percent of theory) was present. A 90 percent yield of t-Bu o was alsoobtained.

EXAMPLE 6 In accordance with the procedure of Example 5, butsubstituting l 1.6 g. of l-methycyclopentylhydroperoxide fort-butylhydroperoxide, and 1.3 g. of the reaction product oforthophosphoric acid and stannous chloride (prepared in accordance withU.S. Pat. No. 2,091,178) for Na stannate, there is obtained a mixture ofdi-l-methylcyclopentylperoxide and hydrogen peroxide in good yield.

EXAMPLE 7 In accordance with the procedure of Example 5, butsubstituting sec.-butylhydroperoxide for t-butylhydroperoxide, there isobtained in good yield a mixture of di-sec.-butylperoxide and hydrogenperoxide.

The foregoing examples show that while hydrogen peroxide is relativelystable in acid concentration alone (Example I), unexpectedly it wasfound to be highly unstable in the presence of both alkylhydroperoxides(Example 3) and the dialkylperoxide product (Example 4). While applicantdoes not wish to be bound by any particular theoretical considerations,it would appear that this is the reason that no hydrogen peroxide wasfound in the prior art conversion of alkylhydroperoxides to thecorresponding peroxide (Example 2 and U.S. Pat. No. 2,522,016).Therefore, by identifying this problem (Examples 3 and 4), and, as shownby Examples 5 to 7, resolving it by finding that certain additives madethe formation of hydrogen peroxide possible in the presence of peroxidesand acid where the art taught that none is evolved, there has beenprovided a novel method, and thus a new source, for obtaining hydrogenperoxide while simultaneously producing di-alkylperoxide.

What is claimed is:

l. A process for the simultaneous production of hydrogen peroxide andaliphatic or alicyclic peroxides which comprises reacting a secondary ortertiary aliphatic or alicyclic hydroperoxide at a temperature of fromabout 40 to 65 C. with an aqueous acid in the presence of from 0.01 to3.0 g. of an alkali metal stannate or the reaction product oforthophosphoric acid and a stannous halide for each 9 to 10 g. ofhydroperoxide starting materiaL-wherein the concentration of the acid isfrom about 30 to 65 weight percent based on the total weight of the acidand water.

2. The process according to claim 1 wherein the stannate salt is sodiumstannate.

3. The process according to claim 1 wherein the acid concentration isfrom about 45 to 55 weight percent based on the total weight of the acidand water.

4. The process according to claim 1 wherein the aliphatic hydroperoxideis t-butylhydroperoxide.

5. A process for the stabilization of hydrogen peroxide in an aqueousacid medium containing an aliphatic or alicyclic peroxide whichcomprises adding from about 0.01 to 3.0 g. of an alkali metal stannateor the reaction product of orthophosphoric acid and a stannous halidefor each 9 to 10 g. of hydroperoxide starting material to said aqueousacidic medium, wherein the concentration of the acid is from about 30 to65 weight percent based on the total weight of the acid and water.

2. The process according to claim 1 wherein the stannate salt is sodiumstannate.
 3. The process according to claim 1 wherein the acidconcentration is from about 45 to 55 weight percent based on the totalweight of the acid and water.
 4. The process according to claim 1wherein the aliphatic hydroperoxide is t-butylhydroperoxide.
 5. Aprocess for the stabilization of hydrogen peroxide in an aqueous acidmedium containing an aliphatic or alicyclic peroxide which comprisesadding from about 0.01 to 3.0 g. of an alkali metal stannate or thereaction product of orthophosphoric acid and a stannous halide for each9 to 10 g. of hydroperoxide starting material to said aqueous acidicmedium, wherein the concentration of the acid is from about 30 to 65weight percent based on the total weight of the acid and water.